This invention relates to a correlator suitable for use in a circuit for cancellation or reduction of unwanted components in two received signals.
Correlators can be employed in circuits for the cancellation or reduction of unwanted components in two received signals. It is known to make use of complex correlators which comprise simple double balanced mixers. These double balanced mixers correlate a high level signal with a low level signal. However, imperfections in the double balanced mixer give rise to a dc offset voltage at the output which is related to the high level input signal. This dc offset voltage can cause an error in the correlator output and thereby reduce the efficiency of any subsequent process for cancelling unwanted components in the two signals. Furthermore, other spurious signals are also generated within the correlator which further increases errors in the correlator output.